Fan for cooling automatic engines

ABSTRACT

A fan for use particularly in cooling truck engines comprises a hub having a plurality of coplanar outwardly extending arms. A plurality of fan blades are secured one on each arm. Each blade is substantially rigid and uniformly arcuate along its entire length. Securing means secure the hub to the engine. Mounting means detachably mount the blades, one on each arm.

United States Patent Primary Examiner-Everette A. Powell, Jr. Attorney- Eugene D. Farley 4/1911 Kincaid 416/197 4/1944 Brotz 416/236 1/1957 Petersime. 416/204 X 3/1958 Page 416/204 6/1967 Myers 416/220 FOREIGN PATENTS 7/1936 Great Britain 416/210 ABSTRACT: A fan for use particularly in cooling truck engines comprises a hub having a plurality of coplanar outwardly extending arms. A plurality of fan blades are secured one on each arm. Each blade is substantially rigid and uniformly arcuate along its entire length. Securing means secure the hub to the engine. Mounting means detachably mount the blades, one on each arm.

l I o PAIENTED DEC H911 3.625535 George H. Siona Ck INVENTOR BY FAN FOR COOLING AUTOMATIC ENGINES This invention relates to fans for cooling internal combustion engines, particularly heavy duty truck engines.

To be suitable for use in cooling heavy duty truck engines in the most efficient and economical manner, the cooling fan must meet the following requirements:

First, it must be rigid and not flatten out at high speeds. The motor of a truck laboring up a hill runs at speeds which flatten out a conventional, flexible fan, causing it to deliver less air. Ventilating air passing through the engine does not compensate for this loss of cooling air since the truck moves at slow speed. Overheating accordingly results.

Second, the fan should remain rigid at high temperatures such as are present during hot weather. If the fan becomes flexible at high temperatures, it tends to flatten out with loss of cooling capacity as noted above.

Third, the blades should be mounted detachably on the fan so that, with a minimum of effort and cost, summer and winter blades may be interchanged and individual damaged blades may be replaced.

Fourth, the blades should be mounted detachably and reversibly for converting a given fan from a puller to a pusher when the engine is used in dusty environments.

Fifth, the fan blades should cut the air cleanly and offer minimum resistance to the air.

Sixth, air recirculation should be kept at a minimum.

Seventh, the blades should be easily manufactured and assembled from a minimum number of parts and provide a long service life.

It is the general object of the present invention to provide a fan meeting the above requirements.

In the drawings:

FIG. 1 is a view in plan of the automotive engine fan of my invention; and

FIG. 2 is a fragmentary end view taken along line 2-2 of FIG. 1.

The fan of my invention includes a hub having extending outwardly therefrom a plurality of arms 12, in the combination commonly known as a spider." A central opening 14 provides access for a shaft, and bolt holes 16 provide means for securing the hub to the rotary member of the engine.

Both hub and arms may be made of a suitable strong structural material, preferably fiberglass. The arms may extend radially, or be pitched at a desired angle. For convenience of manufacture and application, the spider preferably is flat and the arms and hub coplanar with each other.

A plurality of fan blades are mounted one on each of the arms.

Each blade 18 is made of a rigid structural material. Fiberglass again is a preferred material, since it not only is rigid and strong, but it does not soften and become flexible when heated at ordinary engine operating temperatures. The leading edge 20 of the blade preferably is beveled to provide a sharp edge which enters the air with a minimum of resistance.

Arms 18 are longitudinally straight and uniformly arcuate in cross section along their entire length. For maximum efficiency with blades of the usual sizes, the cross sectional arc is chosen to have by a radius of from 2-4 inches, preferably about 3 inches.

Means are provided for detachably mounting the blades on the arms.

In the illustrated form of the invention, such means comprise tongue and groove mounting means with interconnecting fasteners.

The tongue and groove relationship preferably is created by providing on the back of each blade a channel member 22 which receives one of arms 12.

To provide a balanced construction, the channel members preferably join the blades at their longitudinal midpoints.

The angle of the plane of the channel member with respect to the blade is also determinative of the efiiciency of the fan.

.For best results, this angle is measured by that present between the center line of the arm and a line drawn tangent to the blade at its mid int. The angle a should be from 40-80, preferably about 6 Bolts 24 or other suitable fasteners connect the channel members to the arms.

The advantages of the foregoing construction are manifold.

The construction of the arms is such that they may be fabricated from fiberglass or plastic by a simple extrusion process. A long strip first is extruded. This then is subdivided transversely into segments of the desired length.

Since the blades are rigid they do not deflect nor flatten out at high operating temperatures and speeds. The blades are interchangeable simply by unfastening bolts 24. This facilitates replacing a damaged blade, or replacing a set of summer blades with a set of winter blades and vice versa.

The blades cover up the entire spider arms so that air resistance is kept at a minimum. The entire surface of each blade pumps air.

The assembly is balanced so that it does not vibrate.

The blades may be reversed end-for-end so that the fan becomes a pushing type fan rather than a pulling type fan, i.e. it directs air away from the engine rather than toward it.

All of the various advantages are obtained, furthermore, through the provision of a fan which is simply and durably made of a minimum number of parts.

lclaim:

l. A fan comprising:

a. a flat hub having a plurality of integral, coplanar flat arms extending therefrom,

b. securing means for securing the hub to an engine,

c. a plurality of blades,

d. each blade being substantially rigid and substantially uniformly arcuate along its entire length,

e. each blade being provided on its back side with a centrally located, longitudinally extending channel dimensioned to overlie an arm, the channel and blade being integrally extruded from extrudable plastic material, and

f. mounting means detachably mounting the blades on the arms, one on each arm.

2. The fan of claim 1 wherein the cross sectional arc of the blade has a radius of from 2-4 inches. 

1. A fan comprising: a. a flat hub having a plurality of integral, coplanar flat arms extending therefrom, b. securing means for securing the hub to an engine, c. a plurality of blades, d. each blade being substantially rigid and substantially uniformly arcuate along its entire length, e. each blade being provided on its back side with a centrally located, longitudinally extending channel dimensioned to overlie an arm, the channel and blade being integrally extruded from extrudable plastic material, and f. mounting means detachably mounting the blades on the arms, one on each arm.
 2. The fan of claim 1 wherein the cross sectional arc of the blade has a radius of from 2-4 inches. 